[Field epidemiology in times of COVID-19: challenges for public health services. SESPAS Report 2022].

During the COVID-19 crisis, local epidemiology units have been forced to manage an increasing number of cases, contacts and outbreaks for which they were not previously prepared or staffed. Under normal circumstances, the efficient study and control of outbreaks and public health alerts requires human and material resources, situation analysis to identify possible causes and present recommendations, coordination with other health system structures, as well as the providing a written report including control and prevention measures implemented and their results or other recommendations. The field study of outbreaks has been systematized in a way that has made it possible to implement quick and effective measures, for the interruption of transmission chains and management of risk situations. To achieve this, a rapid and extraordinary exercise of digital integration, staff mobilization and creation of ad hoc structures needed to be carried out. Solidarity and cooperation between professionals from different administrations has been the pillar that has sustained the surveillance systems. Despite this, obstacles have been found as a result of the lack of coordination, social inequalities, and later, pandemic fatigue, which have reduced adherence and effectiveness of the implemented measures. It has also come to light the need to properly staff these units with trained professionals, and match working conditions and salaries with other health services.